This application is based on and incorporates herein by reference Japanese Patent Application No. 2001-340380 filed on Nov. 6, 2001.
1. Field of the Invention
The present invention relates to an accumulator vessel in which high-pressure fuel is accumulated in a pressurized state and relates to a method of manufacturing the accumulator vessel.
2. Description of Related Art
A known common rail type fuel injection device for an internal combustion engine, which is referred to as an engine hereafter, accumulates fuel pressurized by a fuel injection pump in an accumulator vessel. The high-pressure fuel accumulated in the accumulator vessel is supplied to a plurality of injectors disposed in correspondence with a plurality of cylinders and is injected to combustion chambers. The injectors are connected with an accumulator chamber formed inside the accumulator vessel by fuel pipes respectively.
Usually, the cylinders are arranged in a straight line. Therefore, the accumulator vessel is formed in a shape of a tube extending along the cylinders to facilitate distribution of the fuel to the respective cylinders. Since the accumulator chamber is supplied with very high-pressure fuel, the accumulator vessel is required to be highly reliable. Therefore, in a method of manufacturing the accumulator vessel, an accumulator chamber hole that provides the accumulator chamber is formed inward from both ends of a rod-shaped member by cutting and the like. In order to ensure fluid-tightness of the accumulator chamber, the accumulator chamber hole is sealed by sealing members attached to both ends of the accumulator chamber hole from the outside of the accumulator vessel.
In the above conventional accumulator vessel, the sealing members are attached to both ends of the accumulator chamber hole by screwing and the like.
However, the sealing members receive forces from the fuel in the accumulator chamber in directions opposite to the screwing directions, since the pressure in the accumulator chamber is very high. Therefore, in order to prevent leak of the fuel from the accumulator chamber and to improve reliability of the accumulator vessel, the screwing torque of the sealing members should be controlled and the connected portions of the accumulator vessel should be machined precisely.
On the other hand, it may be applicable to form a cavity that provides the accumulator chamber from one of the ends of the rod-shaped member by cutting and the like. However, cleaning solution for cleaning the inside of the rod-shaped member is not capable of flowing sufficiently, since only one end of the rod-shaped member is open. Therefore, it is difficult to remove burrs or contaminants produced in the machining.
It is therefore an object of the present invention to provide an accumulator vessel that is easy to clean and is highly reliable.
It is another object of the present invention to provide a method of manufacturing an accumulator vessel that is easy to clean and to assemble.
In an accumulator vessel according to an aspect of the present invention, a sealing member contacts a contacting part formed near a first end of a body member from a second end side. When high-pressure fuel is accumulated in an accumulator chamber hole, the sealing member is biased by the high-pressure fuel toward the contacting part. Accordingly, the sealing member and the contacting part are adhered with each other tightly, so that fluid-tightness is easily ensured without requiring control of screwing force of the sealing member, for instance. Therefore, leak of the fuel from the accumulator chamber is prevented and the reliability of the accumulator vessel is improved. In addition, an accumulator chamber hole interconnects a first opening on the first end of the body member and a second opening on the second end of the body member. Therefore, the cleaning solution flows freely through the accumulator chamber hole and an inside of the accumulator chamber hole is cleaned easily.
In a method of manufacturing an accumulator vessel according to another aspect of the present invention, an accumulator chamber hole is formed, and then, the inside of the accumulator chamber hole is cleaned. Since the accumulator chamber hole interconnects a first opening formed on a first end of a rod-shaped member and a second opening formed on a second end of the rod-shaped member, cleaning solution flows freely through the accumulator chamber hole. Accordingly, the inside of the accumulator chamber hole is cleaned easily, and burrs and contaminants produced in machining of the accumulator chamber hole are removed. A sealing member is inserted into the accumulator chamber hole from the second opening and is fastened so that the sealing member contacts a contacting part formed in the accumulator chamber hole near the first opening. Since the sealing member is merely inserted and fastened to the accumulator chamber hole, control of a screwing torque, for instance, is not required. Therefore, the sealing member is easily attached.